<?php 
if(!isset($_GET['username'])){
echo
'<ul>'.
'<li><a href="#">Chi Siamo</a></li>'.
'<li><a href="#" title="Syndicate this site using RSS 2.0">Informazioni<abbr title="Really Simple Syndication">RSS</abbr></a></li>'.
'<li><a href="#" title="Powered by WordPress, state-of-the-art semantic personal publishing platform.">WordPress.org</a></li>'.
'</ul>';
}
else{ 
echo
'<ul>'.
'<li><a href="#">Logout</a></li>'.
'<li>Estratto conto :<abbr title="Really Simple Syndication">RSS</abbr></a></li>'.
'<li><a href="#" title="Powered by WordPress, state-of-the-art semantic personal publishing platform.">WordPress.org</a></li>'.
'</ul>'; 
}
?>